6i4 THE POPULAR SCIENCE MONTHLY. 



to the observatory. From the first meeting of this commissiou Prof. 

 Newcomb has acted as secretary thereof. Prof. Newcomjb's most 

 recent labors have been on the motion of the moon, and the possible 

 variability of the sidereal day, on which subject he has published 

 several fragmentary discussions. Hansen's tables of the moon have 

 deviated from observation for several years past in a remarkable 

 manner, and he has accounted for the changes by an acceleration in 

 the rotation of the earth on its axis. It is now considered that he 

 has proved the actual existence of this acceleration beyond reason- 

 able doubt. 



In February, 1874, he was the recipient of the gold medal of the 

 Koyal Astronomical Society of Great Britain. The presentation was 

 jjreceded by an address by the president, Prof. Cayley, in which, 

 after giving an account of several of Prof. Newcomb's most important 

 contributions to mathematical science, he says : " They exhibit all of 

 them a combination, on the one hand, of tnathematical skill and power, 

 and, on the other hand, of good hard work, devoted to the furtherance 

 of astronomical science." Thus, though belonging to the younger 

 generation of astronomers, Prof. Newcomb has received his full share 

 of honors, both at home and abroad. Graduating as B. S. at Har- 

 vard University, in 1858, he is now, at home, member of the National 

 Academy of Science, and of the American Academy of Arts and Sci- 

 ences, in Boston. In 1 876 he was elected President of the American 

 Association for the Advancement of Science, and presides at its 

 annual meeting, in Nashville, in August of this year. In 1874 he 

 received the honorary degree of LL. D. from the Columbian Uni- 

 versity, at Washington, and in 1875 the same honor from Yale. 

 Abroad, he was, in 1872, elected associate member of the Royal Astro- 

 nomical Society of Great Britain ; in 1874, corresponding member 

 of the Institut de France ; in 1875 he received the honorary degree of 

 Ph. D. from the University of Leyden, at its three-hundredth anniver- 

 sary. Also in that year he was made a member of the Imperial Acad- 

 emy of Sciences of St. Petersburg, member of the Royal Swedish 

 Academy of Sciences, and member of the Royal Bavarian Academy 

 of Sciences. 



